The most of international shipping cargoes are transported by ship and the shipping market has been continuously increasing. However, due to the recent global recession, the volume of trade decreased accordingly, and the competition between shippers to gain a competitive advantage in the shipping market continues deepening. To do this, researches on transportation costs savings as well as ways to improve customer service are needed and recently related researches are being pursued. Car carriers which transport more than 80% of car import and export volume in the world also make a lot of effort in order to reduce transportation costs, but in contrast related researches are seldom fulfilled. In this study, we developed an agent system that supports the efficient transportation of car carriers plan so that the car carriers can increase competitiveness through reduction of the logistics costs. To make this, we researched an algorithm for maritime transportation planning, and also developed a prototype of an agent system which can collect the necessary information in real time and establish a dynamic plan.